The present disclosure herein relates to a waveguide photodetector, and more particularly, to a waveguide photodetector for detecting incident light traveling along a waveguide.
Waveguide photodetectors is devices in which incident light is coupled to an absorption layer by an optical coupling phenomenon such as an evanescent coupling or a radiation mode, and the light absorbed in the absorption layer is detected as current through an electro-optic conversion when the incident light traveling along a waveguide having a relative higher refractive index than a substrate meets an absorption layer having a refractive index less than that of the waveguide. The waveguide photodetectors have been used for integrated optical devices in which III-V compound semiconductors are mainly used. Waveguide photodetectors that use germanium (Ge) having a refractive index greater than that of upper silicon on a silicon-on-insulator (SOI) substrate as an absorption layer are now being developed.